This document is all about quality. Here is the distribution of wine by quality.
Outliers & Statistical Info

# Statistical information about Volatile Acidity
summary(data$volatile.acidity)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.1200 0.3900 0.5200 0.5278 0.6400 1.5800
There are a few outliers only on the right side.

# Statistical information about Fixed Acidity
summary(data$fixed.acidity)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 4.60 7.10 7.90 8.32 9.20 15.90
There are several outliers only on the right side.

# Statistical information about Total Sulphure Dioxide
summary(data$total.sulfur.dioxide)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 6.00 22.00 38.00 46.47 62.00 289.00
There are many outliers only on the right side.

# Statistical information about Alcohol
summary(data$alcohol)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 8.40 9.50 10.20 10.42 11.10 14.90
There are just a few outliers only on the right side.

# Statistical information about Chlorides
summary(data$chlorides)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.01200 0.07000 0.07900 0.08747 0.09000 0.61100
There are just a few outliers on the left side, and many on the right side.

# Statistical information about Residual Sugar
summary(data$residual.sugar)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.900 1.900 2.200 2.539 2.600 15.500
There are many outliers on the right side.

# Statistical information about pH
summary(data$pH)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 2.740 3.210 3.310 3.311 3.400 4.010
All values are pretty well distributed in the pH variable. There are several outliers on both sides.

# Statistical information about Sulphates
summary(data$sulphates)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.3300 0.5500 0.6200 0.6581 0.7300 2.0000
There are many outliers only on the right side.

# Statistical information about Density
summary(data$density)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.9901 0.9956 0.9968 0.9967 0.9978 1.0037
This variable is also well distributed. There are several outliers on both sides.